Metric wheel nuts have the word Metric stamped on the face. The letter M is stamped at the end of the metric wheel stud.
Thread size of the metric wheel nuts and studs is indicated by the following example:
M12 x 1.5
| • | M = Metric |
| • | 12 = Diameter in millimeters |
| • | 1.5 = Millimeters per thread (gap between) |